Vecna's Rotting Corpse

7 days. Your familiarity with the foul effects of death allows you to prevent a dead body from being returned to life using anything but the most powerful forms of magic. You cast this spell by touching a creature that died within the last 24 hours. The body immediately decomposes to a state that prevents the body from being returned to life by the raise dead spell (though a  resurrection spell still works).

At the end of this spell’s duration, the body decomposes to a rancid slime, and it can’t be returned to life except through a true resurrection spell.